"I've learned to think very rationally about my feelings, and tried to quantify them, even if it seems very crazy still for me," says Gabi.
Instead of doing the things couples normally do, like going out to dinner or a movie, the two of them spend a lot of time and energy promoting his experiment.
Epstein says the relationship is blossoming. And like any good psychologist, he has graphs to prove it.
"The red line here on my graph shows how in love I am with Gabi on a 10-point scale," says Epstein, referring to his graph. "Yesterday, a 4.5, which is pretty good."
"We have a serious problem in this country," says Epstein. "One in two marriages end in divorce. Eighty percent of the people who stay married consider divorce. We need a fix."
But in the therapy sessions, which are at the heart of his experiment, it becomes clear that Epstein's "fix" isn't working. The couple meets with therapist Mark Kaupp and describes an incident that took place on a Manhattan street corner.
"I was just feeling down, very bad, down and depressed," says Epstein. "And the way Gabi reacted actually made me more upset because she said, 'You know, I just can't deal with you when you're like this and I'm going to go off on my own.'"
"He doesn't make an effort. Until I get mad," says Gabi. "And when I get mad, he starts, 'Oh no, don't get mad.'"
Kaupp asks them both if they're making an effort the whole time. Both say yes, but Robert adds, "It's totally different. I'm making an effort to walk and to stand. That to me, I'm making a tremendous effort just to walk and to stand."
"Why do you need me if you have a hard time to even stand? Because you don't want me to touch you, or even be close to you," says Gabi.
After a few more sessions of couples counseling, but little else, Gabi returns to Venezuela, skeptical about her relationship with Epstein.
"For me it's becoming, even though I like him very much now and I have more feelings for him, it's become ... this is only a project, that it's not a relationship."
Back home with family and friends, Gabi makes a momentous decision: "This new concept didn't work for me. Because it had no romance. Without romance in my life, was devastating, deep in my heart."
"That night she called me. Her voice was very, very weak," says Epstein. "And she said, 'I can't do it, I can't do it, I'm not coming back. And she sounded like she was in real turmoil.'"
"It was tense, very tense. But he didn't believe me," says Gabi. "He still doesn't believe me. He wants the idea to work. But it's impossible that he wants this relationship to work because I'm not happy."
Is Epstein more disappointed that the experiment failed, or that he didn't end up with the girl?
"As far as the experiment goes, I'm not disappointed at all. Because the experiment was a complete success. It just didn't go far enough," says Epstein. "The other side of it, the personal side is, at the moment, anyway, the relationship is dead."
Even though his relationship with Gabi failed, Epstein insists his experiment was a "complete success."
And he has a graph, love notes and beautiful emails to prove that the two were falling in love: "At this point, we're saying to each other at times, 'I love you.'"
So what happened? Robert insists that he and Gabi faced "the classic problem of distance and time. Because she's back in another country."
Dr. Robert Epstein, Ph.D., spent nearly a year discovering something most people, even those without a Ph.D., already know: that long-distance relationships rarely work.
Still, he insists his experiment has a future: "The question is, can we package the process? My initial feeling, based on what I've done here so far is yeah, we can."
What did Gabi ultimately think about Epstein's experiment?
"It was very scientific. It was not romantic. But what happens is, for me, that if you don't have romance in your relationship, love can never be born," says Gabi.
"I think if anyone wants to prove a theory, it's very hard to prove it with yourself. And I think it was too much for Robert to be the owner of the idea, to develop the idea, to have this new woman in his life that was a total stranger, totally different to him."
"I miss her tremendously," says Epstein. "She's an incredible person, but on the other hand, she's wrong in a way because she didn't give the process enough of a chance."
What would he say to Gabi now if he had the chance?
"I would like to say, 'I love you,'" he says. "But I'd be lying."
Epstein says he's ready to experiment again, but with another woman. And he's tentatively chosen someone who is local or who can relocate without much trouble.
That's good news for Gabi, who still believes she'll find love -- just with someone else.
"Robert said that you can love many, many persons in your life. You just have to sit down and look around. And I was in an airport and I counted like 10," says Gabi. "And I hope I will find one day Mr. Right or Mr. Whatever that I will share my life with."